Following a high-nutrient diet protects against many chronic diseases, breast cancer included. Overall, consumption of natural plant foods has been associated in numerous studies with reduced risk of breast cancer and improved survival in women with breast cancer.1-5 Since cumulative exposure to estrogen is known to increase breast cancer risk, foods with anti-estrogenic activity are protective — these include cruciferous vegetables, mushrooms, and certain seeds.

Cruciferous vegetables
This family of vegetables includes green vegetables like kale, cabbage, collards, and broccoli plus some non-green vegetables like cauliflower and turnips (see a full list). Cruciferous vegetables contain unique phytochemicals called glucosinolates; when we chop, chew, or blend these vegetables, cell walls are broken, starting a chemical reaction that converts glucosinolates to isothiocyanates (ITCs) — compounds that are protective against all types of cancers — ITCs detoxify and remove carcinogens, kill cancer cells, and prevent tumor growth.6,7 ITCs are also anti-angiogenic, which means that they prevent normal blood vessels from branching off to provide tumors with a blood supply.8

In addition to these general anti-cancer effects, many ITCs are particularly protective against hormone-associated cancers like breast cancer. Eating cruciferous vegetables regularly helps the body to shift hormone metabolism, reducing the cancer-promoting potency of estrogen and other hormones, and increasing hormone excretion.6 In a recent study, women who ate one serving per day of cruciferous vegetables reduced their risk of breast cancer by over 50%.5

Mushrooms
Mushrooms block tumor growth and have anti-estrogenic activity. Frequent consumption of mushrooms (approximately 1 button mushroom per day) has been shown to decrease the risk of breast cancer by 60-70%.9 Mushrooms are thought to protect against breast cancer particularly because they inhibit an enzyme called aromatase, which produces estrogen. Mushrooms are one of the very few foods that inhibit aromatase, and several varieties of mushrooms have strong anti-aromatase activity, including the common varieties like white button and Portobello mushrooms.10

Lignans in flax, chia, and sesame seeds
Lignans are phytochemicals that are structurally similar to estrogen and can bind to estrogen receptors — this capability allows lignans to have protective effects against hormone-related cancers.11,12 Like mushroom phytochemicals, lignans inhibit aromatase13 and estrogen production in general, lowering circulating estrogen levels.14 Plant lignans also increase concentration of sex hormone binding globulin, which blunts the effects of estrogens.15-17 Women with breast cancer who began consuming flaxseed regularly for showed significant tumor cell death after only one month.18 Likewise women eating more flaxseeds with higher levels of circulating lignans were found to have a 42% reduced risk of death from postmenopausal breast cancer and a dramatic (40 percent) reduction in all causes of death.19,20 Flax, sesame, and chia seeds are excellent sources of lignans.

In addition to these foods, don’t forget about the importance of onions, beans, berries, and other whole plant foods that have protective effects against many types of cancers, including breast cancer.

To learn more about super foods with anti-cancer effects, read my book Super Immunity.